#if 0
#include <chrono>
#include <iostream>
#include <thread>
using namespace std;

int main() {
    size_t i = 1;
    while (true) {
        cout << "这是第 " << i++ << " 次循环" << endl;
        this_thread::sleep_for(chrono::seconds(1));
    }

    return 0;
}
#endif

#include <iostream>
#include <string>
using namespace std;

void test() {
    string str = "gdb";
    str += " welcome";
    str += " you";

    cout << str << endl;
}

int main() {
    test();
    return 0;
}